Boring-tool.



No. 787,664. PATBNTED APR. 18, 1905.

M. D. CONVERSE.

BORING TOOL. APPLICATION FILED DEC. 7, 1903.

2 SHEETS-SHEET 1.

' M. D. CONVERSE.

BORING TOOL.

APPLICATION FILED DEC. 7, 1903.

PATENTED APR. 18, 1905.

2 SHEETSSHEET 2.

UNITED STATES Iatented. April is, 1905.

PATENT OFFICE.

BORING-TOOL.

SPECIFICATION forming part of Letters Patent No. 787,664, dated April 18 1905.

Application filed December "7, 1903.v Serial No. 184,186.

To all whom it may concern:

Be it known that I, MASGHIL D. CONVERSE, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented new and useful Improvements in Boring-Tools, of which the following is a specification.

My invention relates to tools for boring, more especially for wood-boring; and it consists of the several devices and the novel construction, arrangement, and combinations of the same hereinafter fully set forth and claimed.

In the drawings, Figure l is avertical side elevation of one form of my invention com plete. Fig. 2 is a cross-sectional view on line :0 is, showing the construction and arrangement of the parts and with a block of wood X in section partially bored through to show the operation of a feature of my invention. Fig. 3 is a lateral end view of the expansible cutter removed or detached from the bitshank. Fig. 4 is a lower end view of Fig. 1,

and Fig. 5 is a similar view with the cutterknife broken away at line 00 00 of Fig. 1. Fig. 6 is an elevation similar to Fig. 1 with an upper portion of the shank broken off, showing a modification of part of my inventionto wit, the cutter and its parts. Fig. 7 is a bottom end view showing a modification and adaptation of parts of my invention, and Fig. 8 is a cross-section on line 00 00 further illustrating the modification shown in Fig. 7 Fig. 9 illustrates the application of a feature of my invention to a common auger. Fig. 10 is a modified construction of my improved expansible cutter, all of which several figures will be hereinafter more fully described in detail.

Like letters indicate corresponding parts throughout the several views.

A is the shank of the bit, (which is shown in Fig. l as having the usual tapered rectangular terminus at its upper end, but which may be of any form required,) the lower end or head of which is preferably made pearshaped, widened on two opposite sides at B B and flattened on the lateral sides at C C. Laterally across the longitudinal center this head is pierced by a hole a, through which a cylindrical arm I) of a cutter c is slidably fitted.

hereinafter referred to.

The surface lines of this arm 6 and the cutting edge (Z of the cutter are parallel and the cutter 0 and the arm I) are preferably integrally connected by a vertical cross-piece or web 0 at one and the same lateral end thereof, which has a sharp edgeon the front at 6, excepting the modification Fig. 10. The upper surface of the arm is flattened at f, and laterally of this fiat surface on one or both sides of the arm is a shoulder or stop 9 except in the modification, Fig. 10. The cutter is provided with a spur h, the point of which, it will be seen, is located on the exact diametral center line of expansible movement, so that its sweep in all adjustments of the cutter compasses a greater radius than any other part of the tool, the efficacy of which will be The surface of the cutter is so beveled at it that it exactly meets tangentially the under sloping surface of the head at j.

At the under surface of the head I) is cut away to make aclearance-channel for escapement of the wood chips when boring.

At the end of the bit and in line with its axis is the lead-screw Z, which may be integrally united to the head, but which I prefer to make removable and to secure by screwthreading its upper end for a portion of its length to enter a correspondingly screwthreaded hole in the head; but as a means to prevent its being unscrewed I construct it with an unthreaded or smooth tapered section on (shown with an exaggerated degree of taper in the figures) to engage a correspondingly-tapered socket counterbored in the end of the head.

A particular feature of my invention consists of the pronounced concave annular groove n in the lead-screw just above the threaded conical portion, the object of which is to cause the bit or auger to be kept to its work without necessity of being pushed by main force of the operator against the wood, as will be hereinafter described.

In the head of the shank A, across the axial center at a point above the center of the hole for the arm 6 and right-angularly to it, another and somewhat smaller hole, 0, is drilled through, so as to intersect the upper margin of the former considerably. Into this is fitted slidablya cylindrical pin 1), the underside of which is tapered by a flattened surface at q for engagement transversely of the upper flattened surface f of the cutter-arm 7). To keep this pin in place against loss, the margins of its ends are slightly turned over or riveted at r r. I prefer to have the tapered end of this pin toward the side of the shank opposite to the side on which the cutter 0 is located, (see Figs. 1, 2, 6, and 10,) but it may be reversed, and in the case of the modification Figs. 7 and 8 it is equivalent to being reversed in part. This pin p serves a double purposeto keep the cutter c, the arm 7) of which it impinges when driven to the left, (see Fig. 2,) from radial movement relatively the axis of the shank A and to keep the edge (Z of the cutter in contact or very nearly to contact with the middle of the neck or concave groove n of the lead-screw, which latter it accomplishes by riding across the slight rearward slope of the flattened top surface f (see Fig.3) of the cutterarm Z). To operate this part of my invention, (see Figs. 2, 3, and 8,) strike the tapered end of the pin 12 against or with any solid object, driving it back, and the arm 5 is instantly free to be moved radially in and out its socket. The cutter can now be expanded to the desired radius, and then by striking the opposite end of the pin in'like manner the cutter and arm are instantly and rigidly bound against movement and the edge (Z of the cutter is also secured against rearward movementor recession from a-proper position close to and across the neck 71. This fastening device in an expansible bit obviates the great trouble and annoyance and loss of time heretofore occasioned by the use of screws for fixing the cutters.

A very important feature of my invention lies in placing the cutting edge (Z of the cutter rearward of the diametral line (see 3/ y, Fig. 4:) of the lead-screw. By this arrangement all of the wood to be removed by boring can be cut away with the expansible cutter unaided by a secondary cutter upon the end of the head B, as is commonly employed and as is necessary in cases where the cutting edge of the expansible cutter passes in front of the diametral line (see y y, Fig. 4) of the lead-screw. In consequence of placing the extreme point of the spur it directly on the diametral center line and plane of expansible adjustment 3/ y, as I do, -it will always describle a circle, (no matter whether set for a large or small hole,) within which all other parts of the bit are contained and cannot crowd, the wall of the hole being bored outward, or drag and crowd the wood to be cut inward, and of course can therefore be made lighter and shorter of dimentions, on which accounts, in conjunction with locating the cutter edge rearward of the diametral line of the lead-screw, (see 1/ y, Fig.

4,) the operation of the tool is much less laborious, and besides will bore a. perfectlysmooth hole and remove all wood without a secondary cutter on the head of the shank. The radius of the extreme curved ends of the cutter, by measure, should be one-half the total length between the vertical parallel lines 8 t, Fig. 1, and will then correspond to the curve of the smallest hole the cutter will bore and operate with least friction. Different lengths of cutters may of course be employed to increase the range of the tool.

Referring to Fig. 2, it will be seen that since the arm 6 and cutter c are integral (see also Fig. 1) as the edge (Z of the latter is forced against the wood the strain naturally tends to rotate the arm 6 in its socket, and therefore tends to force the margin of the flat upper side at u up, so that this action only tends to force the pin into firmer engagement with it by reason of placing the tapered end of the pin in the direction before described. However, in the case of the modifications shown in Figs. 7 and 8, wherein two cutters, by having one-half of their arms cut away on a vertical longitudinal center line are inserted, one from either side sliding past each other Within the hole therefor in the shank, the action on the pin 1), just above described, is from both directions, forward at a, backward at a.

The modification shown at Fig. 6 merely consists of placing the cutter c(and its arm 7) at right angles through the socket) at right angles to the axis of the shank A (instead of diagonally) and is sometimes desirable, especially when the tool is required to do bottomingworkt'. a, boring a hole the bottom of which shall be at right angles to the sides.

The modification shown by Figs. 7 and 8, wherein two expansible cutters are used, is sometimes advantageous, and particularly when holes of large diameter are to be bored or bored in very hard wood. In the former case the cutters are adjusted to cut different diameters and one thereof might be very much longer over all than the other. The advantage of this arrangement is to make the operation less laborious in such cases. The use of the second expansible cutter calls for the cutting of a second clearance-channel is opposite the other, 7r. (See Fig. 8.)

The operation of the concave groove a in the lead-screw is as follows, referring to Fig. 2: As the threaded cone of the screw is screwed into the wood the fiber of the latter is more and more upset and compressed laterally, and the tendency as the cutter finally comes into contact with and begins to cut the wood above is to crowd the lead-screw upward and cause its threads to mar and loose their hold of the wood; but as the last thread sinks below the surface of the wood which the screw has displaced by reason of the concave groove 12/ giving the wood room it immediately expands all round inwardly against the lower inclined or sloping surface 4; thereof, and thus, exerts a strong downward pressure on the screw. This action of the fiber of the wood is clearly seen at w in Fig. 2. This feature of my invention is applicable to common augers, as shown in Fig. 9, in which case the cutting edges (2 of the same terminate at the neck of the groove. It will be understood that the lead-screw may in the case of augers be made detachable by the improved method hereinbefore described. The essential matter of this groove is to have the lower surface a; sloped so that the action on the screw of the expanding wood fiber may be as above described and shown. This device may be advantageously employed in all wood-boring tools requiring a lead-screw.

As will be seen, the modification shown by Fig. 10 relates to construction of the cutter and its members, and this form may be employed with good results and is possibly a little more economical of material and labor in the manufacture. It consists in joining the 5 cutter c and its arm?) at the inner ends there of by the web 6 instead of at the outer ends,

in which case, of course, the spur it remains where it is in the previously-described constructions.

The novel forms of cutter and its members herein described might be secured in place by other means than that shown. Consequently I do not limit myself to the use of the latter. Likewise the latter might be used to secure some other form of cutter. Consequently I do not limit myself to use of'the cutter above.

Parts of my invention may be further modified without departing from the spirit thereof.

The dotted lines .2 .2 in Figs. 3 and 4 indicate how the strength of the web 6 and cutter 0 may be increased by widening the same.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In an expansible boring-bit, a shank having a lead-screw, and a tapered pin fitted transversely through the head part of the shank, in combination with an expansible cutter having an integral arm of cylindrical cross-section and one flattened side adapted to be engaged by said tapered pin and secured in position thereby.

2. In an expansible boring-bit, a shank having a lead-screw, and an expansible cutter having its edge when in operable position located rearward of a diametral lineof the lead-screw center parallel with the main portion of the cutter, in combination with means for adjustably securing said cutter in such rearward position.

3. In an expansible boring-bit, ashank having a lead-screw, and a cutter-armhole transversely of its head, a cutter having an arm parallel to its cutting edge and returned above the horizontal plane of thesame and slidably fitted in the armhole, in combination with means for adjustably securing the cutter just rearward of the lead-screw.

4. In an expansible boring-bit, a shank having a lead-screw, a cutter armhole transversely of its head, a second hole right angularly to the first intersectingits upper margin, and a cutter having an arm with a flat upper surface parallel to its cutting edge and returned above the horizontal plane of the same and slidably fitted in the transverse hole in the head, in combination with a tapered pin slidably fitted in the second hole and adapted to engage the arm transversely and adjustably secure the cutter in position just rearward of the lead-screw.

5. In an expansible boring-bit, a shank carrying an expansible cutter, in combination with an annularly-concave grooved leadscrew.-

6. In an expansible boring-bit, a shank carrying an expansible cutter, in combination with an annularly-concave-grooved detachable lead-screw.

7 In a boring-bit or anger, an annularlyconcave-grooved lead-screw, in combination with cutting edges terminated in the neck of the concave groove.

8. In a boring-bit, or auger, an annularlyconcave grooved detachable lead screw, in combination with cutting edges terminated in the neck of the concave groove.

9. A cutter for an expansible boring-bit having an arm above and parallel to the cutting edge of the cutter united byaweb crosspiece at one of their respective adjacent outer ends.

10. In an expansible boring-bit, a cutter having its edge when in operative position located rearward of a diametral line of the leadscrew parallel with the main portion of the cutter, in combination with a spur having its extreme point located on the said center diametral line of said lead-screw and on theline of radial adjustment.

11. In a dual-cutter expansible boring-bit, cutters having half-round arms above and parallel to the cutting edges,a shank provided with a lead-screw and having a hole transversely the head for adjustably carrying the half-round arms back to back with the cutter edges rearward of the lead-screw, in combination with means for adjustably securing the same in position.

12. In a dual-cutter expansible boring-bit, cutters having half-round arms above and parallel to the cutting edges, the upper edges of which are slightly flattened, a shank provided with a lead-screw and having a hole transing its upper margin, in combination with a to this specification in the presence oftwo Suhtapered pin slidably fitted in the second hole scribing Witnesses. and adapted to engage the upper flattened sur- 1 1 faces of both arms transversely and adjust- MASLHIL (JONVERSE' 5 ably secure the cutters in position just rear- Witnesses:

Ward of the lead-screw. W. E. WRIGHT,

In testimony whereof I have signed my name G. B. SAMMONS. 

